lockdep: Add statistics info for max bfs queue depth

Add BFS statistics to the existing lockdep stats.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1246201486-7308-10-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 1 deletions

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 6358cf7e84b2..744da6265d99 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -929,7 +929,7 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
 
 unsigned long bfs_accessed[BITS_TO_LONGS(MAX_LOCKDEP_ENTRIES)];
 static struct circular_queue  lock_cq;
-
+unsigned int max_bfs_queue_depth;
 static int __bfs(struct lock_list *source_entry,
                         void *data,
                         int (*match)(struct lock_list *entry, void *data),
@@ -975,6 +975,7 @@ static int __bfs(struct lock_list *source_entry,
 
                 list_for_each_entry(entry, head, entry) {
                         if (!lock_accessed(entry)) {
+                                unsigned int cq_depth;
                                 mark_lock_accessed(entry, lock);
                                 if (match(entry, data)) {
                                         *target_entry = entry;
@@ -986,6 +987,9 @@ static int __bfs(struct lock_list *source_entry,
                                         ret = -1;
                                         goto exit;
                                 }
+                                cq_depth = __cq_get_elem_count(cq);
+                                if (max_bfs_queue_depth < cq_depth)
+                                        max_bfs_queue_depth = cq_depth;
                         }
                 }
         }